1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device.
In this specification, a semiconductor device generally means a device which can function by utilizing semiconductor characteristics, and an electrooptic device, a semiconductor circuit, and electronic equipment are all semiconductor devices.
2. Description of the Related Art
A technique by which a transistor (also referred to as a thin film transistor (TFT)) is formed using a semiconductor film formed over a substrate as a channel formation region has attracted attention. The transistor is applied to a wide range of electronic devices such as an integrated circuit (IC) or an image display device (display device). A silicon-based semiconductor material is widely known as a material for a semiconductor film applicable to a transistor. As another material, an oxide semiconductor has been attracting attention.
For example, a transistor including a semiconductor film formed using an amorphous oxide containing indium (In), gallium (Ga), and zinc (Zn) (In—Ga—Zn—O-based amorphous oxide) is disclosed (see Patent Document 1).
When such transistors each including an oxide semiconductor are stacked to have a three-dimensional layered structure, a complex circuit configuration can be formed in a small area. Further, by combination of an integrated circuit formed using a stack of such transistors each including an oxide semiconductor and a transistor which has high field effect mobility and formed using a single crystal silicon substrate, a higher functional circuit can be obtained.